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Hosta 'Blue Elf' PPAF

Common Name: Hosta

This new Hosta from Hans Hansen and Walters Gardens hybridizing delivers what other miniature hostas promised-with truly blue leaves. Compared to the ever popular 'Blue Mouse Ears', 'Blue Elf' has a similar short height but with larger leaves (about 2.5-3" across) and true powdery blue leaves, about the same color as 'Fragrant Blue'. Perfectly proportionate to the size of the plant, shorter flower spikes yield lavender flowers in in midsummer. 'Blue Elf' is the perfect size for fairy gardens or troughs!

Hostas are exceedingly popular perennials in today's gardens due to their versatility in the landscape. Their subtle colors, tall flower scapes, and broad, coarse leaves fill a niche in garden designs that few other plants can achieve. Their large leaves provide excellent coverage for dying bulb foliage. Hostas also grow well in city environments where the air may be polluted by car exhaust, etc.

Hostas grow best in moist, well-drained, highly organic soils with a pH between 5.5 and 7.5. Sandy loam is better than clay because it provides more aeration for the roots. High-filtered or dappled sunlight is necessary for clean, healthy growth. Morning sun is tolerable and will help to intensify the leaf colors, but hot afternoon sun is usually deadly to hostas. They are most at home in shady, woodland settings and often work well as specimen or edging plants.

Especially in northern zones, hostas should be mulched with a layer of finely shredded organic material to prevent heaving in the winter. Mulch is beneficial because it retains moisture around the plant's roots, but it is also the ideal place for slugs to hide. Watch for holes in the center of the leaves. If they are present, so are slugs. Applying a slug bait in early spring when new shoots are beginning to emerge will help to reduce the slug population. After a few years when plants are firmly established, the mulch can be removed completely, which should eliminate the slug problem altogether. Also be sure to clean all hosta foliage out of the garden in early winter after the plants have gone dormant. By doing so, you will be ridding the area of the eggs of slugs and other leaf-eating insects.

Hostas will benefit from a light application of liquid fertilizer (20-10-20 with 50ppm nitrogen) in early spring. Since it is critical to keep all granular fertilizers far from plant crowns to avoid injury, liquid feed is safest. Alternatively, a top dressing of slow release fertilizer may be used. Roots wil rot if too much fertilizer is applied. In the fall, only a light application, if any, is necessary. Apply very little nitrogen in the fall to allow plants to go dormant.

Vernalization:

Required for 10-12 weeks at temperatures below 40° F.

Pests & Diseases:

Aphids are particularly fond of the new growth. If they feed excessively, the leaves may appear disfigured when they unfurl. Applications of Orthene, Botanigard, or Thiodan are effective at preventing aphids. Applications of Avid, Talstar, or predatory mites are effective on some varieties of hostas which are susceptible to spider mites. Slugs tend to seek out hostas. Good greenhouse sanitation before potting is the best way to prevent a slug outbreak. Additionally, Mesurol can be used as a spray to knock down an existing slug population. Mice also enjoy a tasty meal of hosta roots and crowns. Prevent rodent problems by using a bait such as D-Con or by using traps.

Potting & Timing:

Potting soil should be a well drained, bark based, soil-less mix. Use a pot that corresponds with the size of the roots. Giving roots the space they need will allow plants to reach their optimum size and quality. When transplanting, it is best to spread or fan out the roots since this tends to encourage new growth. When transplanting in spring, keep hostas at 50° F for the first two weeks to promote root growth. Minimum temperatures may then be lowered to 40° F.

Moisture:

The best root development occurs when plants are allowed to dry out slightly between waterings. It is best to water early in the morning. As with all plants, it is important not to over-feed or over-water. Keep soil moist early in the growing season, but do not overwater. Later in the season, allow soil to dry out between waterings. Dormant hosta require very little water. Severe or prolonged dry conditions on the other hand, may force hostas into dormancy.

Planting Level:

Growing points or 'eyes' should be at or just below the soil surface.

Lighting:

Long days encourage new foliage growth.

Other Comments:

Overwintering InformationPotted hosta can be overwintered in the same manner as most other potted perennials. After applying a fungicide drench, we suggest using the following overwintering procedures based on our experience in Midwest climate:

In a cold frame structure - Turn larger pots on their side if possible. Cover with a layer of microfoam and a layer of white copolymer. Be sure to remove this covering in early Spring. Bait liberally for mice. Although cold frames are low in cost, this method is not preferred because the plants become exposed to extreme temperature changes along with excessive wind and moisture once the covering is removed in Spring. This can cause foliage and root damage, and possibly the loss of plants.

Unheated overwintering structures covered with a white copolymer - This is an ideal method of overwintering potted hostas. With this method, the pots are placed inside the unheated structure and covered with microfoam. Although the microfoam is removed in early Spring, the white copolymer can remain on the houses for some additional time, making this method preferable over cold fram structures. Hostas will develop naturally in this environment and yet be protected from the extreme weather conditions of Spring. As an added bonus, the ends of the houses can be opened for ventilation. As the warmer days of Spring arrive, the white copolymer can be removed and replaced with 50% shade cloth for contined growing. A 70% shade cloth is recommended for blue hostas as it will help hold their blue color longer in the season.

Minimal heat polyhouses (around 35° F) - We do not recommend growing potted hostas in a warm house since they require a prolonged cold treatment in order to break dormancy. Normally, hostas grow in in a minimal heat polyhouse develop faster than in their natural environment. Advanced foliage on hosta cannot be hardened off and damage can occur if exposed to cold temperatures.

Hostas grow best in moist, well-drained, highly organic soils with a pH between 5.5 and 7.5. Sandy loam is better than clay because it provides more aeration for the roots. High-filtered or dappled sunlight is necessary for clean, healthy growth. Morning sun is tolerable and will help to intensify the leaf colors, but hot afternoon sun is usually deadly to hostas. They are most at home in shady, woodland settings and often work well as specimen or edging plants.

Especially in northern zones, hostas should be mulched with a layer of finely shredded organic material to prevent heaving in the winter. Mulch is beneficial because it retains moisture around the plant's roots, but it is also the ideal place for slugs to hide. Watch for holes in the center of the leaves. If they are present, so are slugs. Applying a slug bait in early spring when new shoots are beginning to emerge will help to reduce the slug population. After a few years when plants are firmly established, the mulch can be removed completely, which should eliminate the slug problem altogether. Also be sure to clean all hosta foliage out of the garden in early winter after the plants have gone dormant. By doing so, you will be ridding the area of the eggs of slugs and other leaf-eating insects.

Hostas will benefit from a light application of liquid fertilizer (20-10-20 with 50ppm nitrogen) in early spring. Since it is critical to keep all granular fertilizers far from plant crowns to avoid injury, liquid feed is safest. Alternatively, a top dressing of slow release fertilizer may be used. Roots wil rot if too much fertilizer is applied. In the fall, only a light application, if any, is necessary. Apply very little nitrogen in the fall to allow plants to go dormant.

Vernalization:

Required for 10-12 weeks at temperatures below 40° F.

Pests & Diseases:

Aphids are particularly fond of the new growth. If they feed excessively, the leaves may appear disfigured when they unfurl. Applications of Orthene, Botanigard, or Thiodan are effective at preventing aphids. Applications of Avid, Talstar, or predatory mites are effective on some varieties of hostas which are susceptible to spider mites. Slugs tend to seek out hostas. Good greenhouse sanitation before potting is the best way to prevent a slug outbreak. Additionally, Mesurol can be used as a spray to knock down an existing slug population. Mice also enjoy a tasty meal of hosta roots and crowns. Prevent rodent problems by using a bait such as D-Con or by using traps.

Potting & Timing:

Potting soil should be a well drained, bark based, soil-less mix. Use a pot that corresponds with the size of the roots. Giving roots the space they need will allow plants to reach their optimum size and quality. When transplanting, it is best to spread or fan out the roots since this tends to encourage new growth. When transplanting in spring, keep hostas at 50° F for the first two weeks to promote root growth. Minimum temperatures may then be lowered to 40° F.

Moisture:

The best root development occurs when plants are allowed to dry out slightly between waterings. It is best to water early in the morning. As with all plants, it is important not to over-feed or over-water. Keep soil moist early in the growing season, but do not overwater. Later in the season, allow soil to dry out between waterings. Dormant hosta require very little water. Severe or prolonged dry conditions on the other hand, may force hostas into dormancy.

Planting Level:

Growing points or 'eyes' should be at or just below the soil surface.

Lighting:

Long days encourage new foliage growth.

Other Comments:

Overwintering InformationPotted hosta can be overwintered in the same manner as most other potted perennials. After applying a fungicide drench, we suggest using the following overwintering procedures based on our experience in Midwest climate:

In a cold frame structure - Turn larger pots on their side if possible. Cover with a layer of microfoam and a layer of white copolymer. Be sure to remove this covering in early Spring. Bait liberally for mice. Although cold frames are low in cost, this method is not preferred because the plants become exposed to extreme temperature changes along with excessive wind and moisture once the covering is removed in Spring. This can cause foliage and root damage, and possibly the loss of plants.

Unheated overwintering structures covered with a white copolymer - This is an ideal method of overwintering potted hostas. With this method, the pots are placed inside the unheated structure and covered with microfoam. Although the microfoam is removed in early Spring, the white copolymer can remain on the houses for some additional time, making this method preferable over cold fram structures. Hostas will develop naturally in this environment and yet be protected from the extreme weather conditions of Spring. As an added bonus, the ends of the houses can be opened for ventilation. As the warmer days of Spring arrive, the white copolymer can be removed and replaced with 50% shade cloth for contined growing. A 70% shade cloth is recommended for blue hostas as it will help hold their blue color longer in the season.

Minimal heat polyhouses (around 35° F) - We do not recommend growing potted hostas in a warm house since they require a prolonged cold treatment in order to break dormancy. Normally, hostas grow in in a minimal heat polyhouse develop faster than in their natural environment. Advanced foliage on hosta cannot be hardened off and damage can occur if exposed to cold temperatures.